Patient fulfill inclusion criteria and consent to surgery and study will be recruited. A standardized pre-peritoneal dissection and mesh placement will be adopted. Immediately before deflation of pre-peritoneal space, randomization will be performed by calling research assistant for study group using computer generated code. Drain will be placed for 23 hours after operation and ultrasonography will be performed immediately after removal of drain. USG will be repeated at post-operative 1 week, 1 month, 3 months, 6 months and 1 year after surgery. For non-drain group, a fake drain will be attach to the skin of the wound to achieve double blinding to patients and assessors. In addition to seroma, patient demographics and secondary outcome including post-operative pain score, discomfort, foreign body sensation, patient satisfaction, infection, recurrence, etc will be studied.